ThunderMax Electrical Issues - Marelli and Early Delphi Systems User Manual
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Note- A working, yet faulty, IAC motor will provide erratic A/F readings
and poor performance. Replacing the IAC motor is a quick process
worth trying.
Fuse Panel
Corrosion at the terminals of the fuse panel, data port or other
connectors is commonly found. Terminal corrosion may be hidden,
and may require the removal, inspection and cleaning/repair of the
fuse panel.
ECM Harness Connector
Corrosion may also be found in the ECM harness terminal.
Disassembly and careful inspection of the ECM terminals and
housing will be required to properly diagnose a problem.
Thoroughly clean any corrosion and repair any weak, broken or
questionable wiring as needed. The image below shows damage to
a Marelli model ThunderMax ECM as a result of power washing a
motorcycle with the side cover removed, water invades past the
seal entering the harness connector and settling around the ECM
connector blades.